Regarding the meanings of por·neiʹa, B. F. Westcott in his book Saint Paul’s Epistle to the Ephesians (1906, p. 76) says: “This is a general term for all unlawful intercourse, (I) adultery: Hos. ii. 2, 4 (LXX.); Matt. v. 32; xix. 9; (2) unlawful marriage, I Cor. v. I; (3) fornication, the common sense as here [Eph 5:3].”

In fact, he warns that it should not even be a topic of conversation among Christians, who should be holy. Similarly, the Israelites were not to mention the names of the pagan gods​—not that they would fail to warn their children about these gods, but they would not mention them with any esteem.​—Eph 5:3; Ex 23:13.